Once work begins, hold brief daily meetings to discuss the job and schedule and quash any misunderstandings. If there are surprises, seek middle ground. No contract can anticipate every possibility. Materials may be unavailable. Large chunks of rotten siding may crumble along with the old paint. Exterior jobs may be stopped cold by a week of steady rain. But know that you'll pay extra if you change your mind about a color after the trim is already painted or otherwise add tasks to the project.
These are some fantastic questions to ask and I particularly like the one that is concerned about safety for the painters. After all, if you have a large home and you’re hiring them to paint the exterior of that home then they’ll likely be on scaffolding. Because of that, you need to make sure that the contractor not only provides appropriate safety training, but has the correct liability insurance as well.